1. Field of the Invention
The invention relates to systems for retractably positioning a cover over an opening of a space to be enclosed and, more particularly, to systems for retractably positioning a cover over a swimming pool.
2. State of the Art
The use of swimming pool covers on conventional residential-type swimming pools is well known and examples of such are described in U.S. Pat. No. 5,913,613 (Ragsdale et al.) and U.S. Pat. No. 5,920,922 (Ragsdale et al.). As discussed in the foregoing references, pool covers are becoming standard equipment for maximizing pool safety as well as reducing unwanted debris from entering the swimming pool when not in use. In addition, the use of pool covers reduces heat loss from heated pool water and can also be used to absorb the sun""s rays to heat the pool water during daylight hours.
Many motorized pool-covering apparatuses include a recessed well or a raised housing positioned at one end thereof and have mounted therein an elongated drum fixed to a rotatable shaft which in turn is connected to an electric motor. An impervious, flexible pool cover is secured, at one of its ends, to the cover-collecting drum and is collectable thereon by rotational movement of the drum. The pool cover is extended over the top of the swimming pool by attaching draw cords to both sides of the pool cover as longitudinal extensions thereof and extending the draw cords the length of the pool and around a pulley rotatably fixed to the other side thereof. On most of the pool covers now in use, the draw cord is returned and secured to a collecting reel which is rotatably carried on the same elongated shaft that carries the cover-collecting drum. In some versions, one collecting reel is carried on one side of the drum and the other is carried on the other side. In other versions, both reels are positioned next to each other with pulleys positioned to direct the draw cords to the appropriate reel. A clutching mechanism is used to engage the drum or reels to affect opening and closing.
The prior art systems, although effective for the purposes designed, on occasion damage the pool cover fabric during the time it is being retracted on the collecting drum. Tearing or ripping of the cover fabric can occur when one side of the cover fabric is collected on the drum at a rate faster than the other side. Eventually, the cover fabric is damaged. Systems to avoid this problem and to avoid costly repairs of the pool cover fabric are not known.
A system for extending and retracting a cover, which is sometimes called a fabric, over an opening of a space to be enclosed includes a cover which is shaped and sized for positioning over the opening of the space to be enclosed. The cover is moveable between a closed position in which the cover substantially covers the opening and an open position in which the cover is displaced from the closed position. The cover has a front edge, a first side edge and a second side edge spaced from the first side edge. The first side edge has a length and a first plurality of bead members disposed along the length. The second side edge has a length and a second plurality of bead members disposed along the length.
A first guide track is positioned proximate the opening. The first guide track has a length and preferably a race or a cutout portion configured to guide said first plurality of bead members along the length upon movement of said cover between said open position and said closed position. A second guide track is positioned proximate the opening to be covered and is spaced from the first guide track. The second guide track also has a length, a first end and preferably a race or a cutout portion configured to guide the second plurality of bead members upon movement of the cover between the open position and the closed position.
A first positive drive is a suitable mechanism for urging the beads of said first plurality of beads into or out of the race. At present, the first positive drive has a first bead sprocket and a housing. The first bead sprocket has a circumferential wall and a plurality of inverse teeth positioned there through, each one of the plurality of inverse teeth being sized and configured to engage a portion of a corresponding one of the first plurality of guide beads. The housing has a first end positioned proximate the first end of the first guide track and a receiving surface configured to receive a portion of the circumferential wall of the bead sprocket. The receiving surface has a recess portion positioned there through and configured to guide the first plurality of guide beads along the receiving surface. The recess portion communicates with the cutout portion of the first guide track.
A second positive drive is also a suitable mechanism for urging the beads of said first plurality of beads into or out of the race. At present the second positive drive has a second bead sprocket and a housing. The second bead sprocket has a circumferential wall and a plurality of inverse teeth positioned there through, each one of the plurality of inverse teeth being sized and configured to engage a portion of a corresponding one of the second plurality of guide beads. The housing has a first end positioned proximate the first end of the second guide track and a receiving surface configured to receive a portion of the circumferential wall of the bead sprocket. The receiving surface has a recess portion positioned there through and configured to guide the second plurality of guide beads along the receiving surface. The recess portion communicates with the cutout portion of the second guide track.
A drive means rotates the first bead sprocket and the second bead sprocket of the first and second positive drives, respectively. The drive means can be electric, hydraulic or manually operated. A take-up drum is connected to one of the bead sprockets by a pulley and belt arrangement and functions to collect the cover when in the retracted or partially retracted position.